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076. Investigating Outcomes following Endoscopic Third Ventriculostomy (ETV) with/without Choroid Plexus Cauterization (CPC) in Patients with Aqueductal Stenosis (AS) plus Cerebral Malformations (AS+)

Authors: Jonathan A. Pindrik, MD, FAANS

Introduction:
Endoscopic third ventriculostomy (ETV) with or without choroid plexus cauterization (CPC) represents a popular therapy for obstructive hydrocephalus due to aqueductal stenosis (AS). Unreported in published literature, patients with AS plus genetic and/or neurologic syndromes with cerebral malformations (AS+) may respond poorly to ETV/ETV-CPC, a hypothesis investigated in this study.Methods: This single institution retrospective review investigated electronic medical records and prospectively collected data within the Hydrocephalus Clinical Research Network (HCRN) for pediatric patients with AS or AS+ undergoing ETV or ETV-CPC from 12/2016 through 06/2021. Demographic and clinical data, new onset post-operative seizures, and frequency of ETV/ETV-CPC failure requiring shunt insertion were summarized using descriptive statistics and compared to published outcomes. Treatment outcomes were compared to ETV success scores (ETVSS), a validated percent prediction of ETV success.
Results:
Twenty-one subjects total (AS, 12; AS+, 9) underwent ETV/ETV-CPC. Among 12 subjects with isolated AS (median and mean age at surgery, 142.7 months and 122.8 months +/- 78.8 months, respectively), none (0%) experienced ETV/ETV-CPC failure with mean follow-up 22.2 months +/- 17.9 months, comparing favorably with related published hydrocephalus outcomes. Among 9 subjects with AS+ (median and mean age at surgery, 2.3 months and 27.3 months +/- 51.0 months, respectively), 3 (33%) experienced new onset seizures and 7 (78%) experienced ETV/ETV-CPC failure with mean follow-up 19.0 months +/- 13.6 months, exceeding relevant published frequencies for post-operative seizure (1-5%) and treatment failure (18-51%) in AS. Treatment success rates for subjects with AS (100%) exceeded the sample mean ETVSS (82% +/- 12%) while success rates for subjects with AS+ (22%) fell below the sample mean ETVSS (53% +/- 19%).
Conclusion:
Patients with AS+ responded poorly to ETV/ETV-CPC regarding seizure and hydrocephalus outcomes. Larger retrospective and prospective studies through the HCRN are needed to verify these preliminary results and justify alternative therapy with shunt insertion.